Baba T, Azuma S, Kashiwabara S, Toyoda Y
Institute of Applied Biochemistry, University of Tsukuba, Ibaraki, Japan.
J Biol Chem. 1994 Dec 16;269(50):31845-9.
The physiological function of mammalian sperm acrosin has long been believed to be involved in the limited proteolysis of the oocyte zona pellucida, thus enabling the sperm to penetrate this extracellular matrix and to gain access to the oocyte plasma membrane. Here we show that male mice homozygous for a targeted mutation in the mouse acrosin gene are still fertile in spite of the complete absence of acrosin protease activity in the sperm. In vitro fertilization assays verified that sperm from the homozygous mutant mice penetrate the zona pellucida and effect fertilization. Therefore, acrosin is not essential for both sperm penetration of the zona pellucida and fertilization.
长期以来，人们一直认为哺乳动物精子顶体蛋白酶的生理功能与卵母细胞透明带的有限蛋白水解有关，从而使精子能够穿透这种细胞外基质并接触到卵母细胞质膜。在此，我们表明，尽管小鼠顶体蛋白酶基因发生靶向突变的纯合雄性小鼠精子中完全没有顶体蛋白酶活性，但它们仍然具有生育能力。体外受精试验证实，纯合突变小鼠的精子能够穿透透明带并实现受精。因此，顶体蛋白酶对于精子穿透透明带和受精都不是必需的。
